The invention relates to the technical field of single-use instruments customized for the patient for the installation of orthopedic implants, especially for a prosthesis of the shoulder joint.
More specifically, the invention relates to a customized humeral jig for the installation of a shoulder prosthesis, especially of reverse type.
It should be reminded that “reverse shoulder joint prosthesis” designates a prosthesis having its hemispherical condyle, as such, attached at the level of the glenoid cavity to cooperate with a cup or platen of complementary shape, and fixed on a humeral stem. In other words, in this type of prosthesis, the glenoid implant comprises a hemispherical condyle while the humeral implant comprises a cup or platen.
It is now admitted that the fixing and the positioning of prosthetic implants are particularly important for the success of the biomechanical operation of the shoulder prosthesis and its lifetime.
An advantageous solution for the installation of a shoulder prosthesis comes out from the teachings of document FR 2967047 also assigned to the applicant hereof.
This document relates to a jig for installing a shoulder prosthesis on a glenoid cavity by planning in 3 dimensions the installation of the implant based on scanner or RMI images.
The 2D images are processed by means of specific software enabling to segment the bone areas of interest for the installation, with the purpose of reconstructing a three-dimensional structure. Landmarks enabling to determine a specific coordinate system in the scapular bone are defined on this structure in the case of the previously-mentioned document.
This three-dimensional model enables to accurately simulate, plan, and measure the orientation of the prosthetic implant according to the previously-mentioned coordinate system.
The operator plans not only the size and the positions of the considered implant, but also compares in the 3 planes of space the joint geometry with and without a prosthesis according to the selected elements.
In other words, the desired aim is to form an installation jig customized for the patient, which enables to reconstruct on the patient the simulation performed by means of the planning software.
Based on the state of the art defined by the teachings of document FR 2967047, the problem that the present invention aims at solving is to form a customized installation jig in the case of a humeral implant.